Monitor Varanus Research Articles

Active forest nesting site, mating and cannibalistic oophagy behaviour in the Asian water monitor Varanus salvator

Active forest nesting site, mating and cannibalistic oophagy behaviour in the Asian water monitor Varanus salvator

Activity budget of Bengal Monitor Varanus bengalensis: Effect of daytime, season, age and temperature

The Bengal Monitor (Varanus bengalensis) is a large, ecologically flexible species and commonly found in many ecological settings including human-modified habitats. We conducted a study on the activity budget of this species employing the focal sampling method in the Chandpur district of Bangladesh. The Bengal Monitor spent the highest proportion of time in resting (33.09%) and the least proportion (3.75%) of time in anti-predatory behavior. The proportion of time spent on each activity by Bengal Monitor varied significantly between age classes and seasons except anti-predatory behavior. The highest proportion of basking activity was recorded for adult and sub-adult individuals in the dry season. Meanwhile, resting and foraging behavior was higher during the wet season. Locomotion activities were higher in sub-adults than in adult individuals. The duration of the activities did not differ significantly for daytime and season. However, an increase of air temperature significantly impacted lowering basking and rising locomotion activities among all behaviors of adult Bengal Monitor. The present findings suggest that the activities of the Bengal Monitor varied according to temporal and seasonal changes in the habitat's temperature, and age may crucially affect the allocation time for different activities.

Himalayan upliftment and Shiwalik succession act as a cradle for divergence in Bengal monitor lizard Varanus bengalensis (Reptilia: Varanidae) in India.

The Himalayan foothills and associated environment are well-known for driving the rapid diversification of many species and the formation of biodiversity hotspots. The effects of environmental change since the Miocene have accelerated species diversification, and hence are useful for studying population genetic structure, and evolutionary relationships via genetic approaches. To date, the effects of climatic fluctuations on the biogeography of large-bodied lizards have not been assessed comprehensively. Herein, we examine the diversification of Varanus bengalensis, focusing on its genetic structure to provide insights into how landscape structure and climatic fluctuations have shaped species differentiation. We confirm the existence of two distinct lineages within V. bengalensis distributed across the Himalayan foothills and the remainder of mainland India. Divergence analyses revealed the split between the Himalayan foothills and the remainder of the mainland lineages of V. bengalensis in the mid-Pliocene ~3.06 Ma, potentially as a consequence of the Siwalik broadening and climatic fluctuations across the Himalayan foothills. The results suggest recognition of a new lineage of V. bengalensis from the Himalayan foothills as a distinctive evolutionarily significant unit.

Range extension and new ecoregion records of the Crocodile Monitor Varanus salvadorii (Peters & Doria, 1878) (Reptilia: Varanidae) in Papua New Guinea

The Crocodile Monitor Varanus salvadorii is one of the longest lizards and an apex predator in New Guinea. Limited information is available on its ecology and distribution, mainly due to its arboreal lifestyle and preference for inaccessible primary forest habitats. Here we provide the first published record, using camera trapping technology in the Torricelli Mountain Range, of V. salvadorii living at a higher elevation than previously recorded in montane rainforest habitat. This range extension implies the occupation of a distinctive ecoregion for the species: the Northern New Guinea Montane Forest, a substantially cooler region from the formerly known distribution area. We present trail camera images of an active animal at an elevation of 1,500 m & at 18oC temperature and we discuss the implications of this finding for understanding the behaviour & conservation of the Crocodile Monitor.

Brumation of the clouded monitor lizard Varanus nebulosus in north-eastern Thailand

The clouded monitor lizard (Varanus nebulosus), is a semi arboreal lizard widely distributed throughout much of South and Southeast Asia. Despite its wide distribution there is almost nothing known about the ecology of this species. During the course of an 11-month radio telemetry study, in a reserve with a tropical savannah climate (Köppen Aw), we made the first records of brumation in this monitor lizard. This contrasts with earlier reports of the same species in a tropical monsoon climate (Köppen Am) where no brumation was recorded. We successfully tracked 10 individuals throughout their inactive period and found that seven of the monitors selected tree hollows within the endangered Shorea henryana tree. All tree hollows selected faced between the east and south cardinal points (90 °-180 °). The average brumation period was 100 days (range 86-113 days, standard deviation - 10.7), beginning in November at a time of falling temperatures and humidities and ending in early March when these variables had been restored. Eight of the 10 monitors basked partially or completely out of their shelters on multiple occasions. Of those eight monitors, two individuals moved between shelters during brumation after an extended period in one location. Our observations provide insight into the relationship between V. nebulosus and the tree S.henryana, in the dry evergreen forests of north-eastern Thailand. Future research should investigate how this tree will be affected by climate change in the coming decades and what that could mean for the future persistence of the clouded monitors that appear to rely on it

03. Brumation of the clouded monitor lizard Varanus nebulosus in north-eastern Thailand

The clouded monitor lizard (Varanus nebulosus), is a semi arboreal lizard widely distributed throughout much of South and Southeast Asia. Despite its wide distribution there is almost nothing known about the ecology of this species. During the course of an 11-month radio telemetry study, in a reserve with a tropical savannah climate (Köppen Aw), we made the first records of brumation in this monitor lizard. This contrasts with earlier reports of the same species in a tropical monsoon climate (Köppen Am) where no brumation was recorded. We successfully tracked 10 individuals throughout their inactive period and found that seven of the monitors selected tree hollows within the endangered Shorea henryana tree. All tree hollows selected faced between the east and south cardinal points (90 °-180 °). The average brumation period was 100 days (range 86-113 days, standard deviation - 10.7), beginning in November at a time of falling temperatures and humidities and ending in early March when these variables had been restored. Eight of the 10 monitors basked partially or completely out of their shelters on multiple occasions. Of those eight monitors, two individuals moved between shelters during brumation after an extended period in one location. Our observations provide insight into the relationship between V. nebulosus and the tree S.henryana, in the dry evergreen forests of north-eastern Thailand. Future research should investigate how this tree will be affected by climate change in the coming decades and what that could mean for the future persistence of the clouded monitors that appear to rely on it.

Concerted and Independent Evolution of Control Regions 1 and 2 of Water Monitor Lizards (Varanus salvator macromaculatus) and Different Phylogenetic Informative Markers.

Simple SummaryThe evolutionary patterns and phylogenetic utility of duplicate control regions (CRs) in 72 individuals of Varanus salvator macromaculatus and other varanids have been observed. Divergence of the two CRs from each individual revealed a pattern of independent evolution in CRs of varanid lineage. This study is a first step towards developing new phylogenetic evolutionary models of the varanid lineage, with accurate evolutionary inferences to provide basic insights into the biology of mitogenomes.Duplicate control regions (CRs) have been observed in the mitochondrial genomes (mitogenomes) of most varanids. Duplicate CRs have evolved in either concerted or independent evolution in vertebrates, but whether an evolutionary pattern exists in varanids remains unknown. Therefore, we conducted this study to analyze the evolutionary patterns and phylogenetic utilities of duplicate CRs in 72 individuals of Varanus salvator macromaculatus and other varanids. Sequence analyses and phylogenetic relationships revealed that divergence between orthologous copies from different individuals was lower than in paralogous copies from the same individual, suggesting an independent evolution of the two CRs. Distinct trees and recombination testing derived from CR1 and CR2 suggested that recombination events occurred between CRs during the evolutionary process. A comparison of substitution saturation showed the potential of CR2 as a phylogenetic marker. By contrast, duplicate CRs of the four examined varanids had similar sequences within species, suggesting typical characteristics of concerted evolution. The results provide a better understanding of the molecular evolutionary processes related to the mitogenomes of the varanid lineage.

Genetic characterisation of Tanqua (von Linstow, 1879) (Nematoda: Gnathostomatidae) larval forms including new host and locality records.

In an unrelated study of spotted snakehead fish Channa punctata (Bloch) of family Channidae (N = 103) from Bangladesh, ten fish had taupe and clear coloured cysts attached to the intestinal mesentery. Investigation of the cysts revealed larval nematodes. The larvae were damaged and not suitable for detailed morphological study, however, key features such as tooth like projections of the pseudolabia and lateral pseudolabium were observed in specimens with undamaged cephalic regions. Molecular characterisation was undertaken and although the parasite genetic material was poor, five of the twelve nematode larvae through sequencing of the 18S ribosomal RNA gene, showed 98.17% match with sequences assigned for Tanqua tiara (accession number JF934728) deposited in GenBank. The prevalence of infection was 9.7% and the mean intensity 2.70. Tanqua has not previously been identified in fish, or from the definitive host, the Asian water monitor Varanus salvator (Laurenti, 1768) of family Varanidae (class Reptilia), in Bangladesh. Therefore, this study represents a new host and locality record for this nematode species. In many previous reports from this region, nematode larvae have been identified morphologically and assigned to a diverse range of nematode genera. Some confusion therefore exists regarding their accuracy and further investigations are required using molecular methodology to clarify the species of larval nematodes which infect edible fish in Bangladesh.

Apparent density, trypanosome infection rates and host preference of tsetse flies in the sleeping sickness endemic focus of northwestern Uganda

BackgroundAfrican trypanosomiasis, caused by protozoa of the genus Trypanosoma and transmitted by the tsetse fly, is a serious parasitic disease of humans and animals. Reliable data on the vector distribution, feeding preference and the trypanosome species they carry is pertinent to planning sustainable control strategies.MethodologyWe deployed 109 biconical traps in 10 villages in two districts of northwestern Uganda to obtain information on the apparent density, trypanosome infection status and blood meal sources of tsetse flies. A subset (272) of the collected samples was analyzed for detection of trypanosomes species and sub-species using a nested PCR protocol based on primers amplifying the Internal Transcribed Spacer (ITS) region of ribosomal DNA. 34 blood-engorged adult tsetse midguts were analyzed for blood meal sources by sequencing of the mitochondrial cytochrome c oxidase 1 (COI) and cytochrome b (cytb) genes.ResultsWe captured a total of 622 Glossina fuscipes fuscipes tsetse flies (269 males and 353 females) in the two districts with apparent density (AD) ranging from 0.6 to 3.7 flies/trap/day (FTD). 10.7% (29/272) of the flies were infected with one or more trypanosome species. Infection rate was not significantly associated with district of origin (Generalized linear model (GLM), χ2 = 0.018, P = 0.895, df = 1, n = 272) and sex of the fly (χ2 = 1.723, P = 0.189, df = 1, n = 272). However, trypanosome infection was highly significantly associated with the fly’s age based on wing fray category (χ2 = 22.374, P < 0.001, df = 1, n = 272), being higher among the very old than the young tsetse. Nested PCR revealed several species of trypanosomes: T. vivax (6.62%), T. congolense (2.57%), T. brucei and T. simiae each at 0.73%. Blood meal analyses revealed five principal vertebrate hosts, namely, cattle (Bos taurus), humans (Homo sapiens), Nile monitor lizard (Varanus niloticus), African mud turtle (Pelusios chapini) and the African Savanna elephant (Loxodonta africana).ConclusionWe found an infection rate of 10.8% in the tsetse sampled, with all infections attributed to trypanosome species that are causative agents for AAT. However, more verification of this finding using large-scale passive and active screening of human and tsetse samples should be done. Cattle and humans appear to be the most important tsetse hosts in the region and should be considered in the design of control interventions.

Optimal cooling rates for sperm cryopreservation in a threatened lizard conform to two-factor hypothesis of cryo-injury

Assisted reproductive technologies provide important tools for wildlife conservation but have rarely been developed for reptiles. A critical step in developing cryopreservation protocols is establishing optimal cooling rates for cell survival. The two-factor hypothesis explaining cryoinjury to cells originates from an inverted ‘U’ shape of recovery curves generated in many cell types thawed after cryopreservation, due to cell recovery declining at cooling rates either side of a single optimum. We generated such a curve for the yellow-spotted monitor lizard Varanus panoptes, the first for any reptile. We cryopreserved sperm using two cooling devices (LN2 dry shipper; LN2 bath vapour) and two sperm-holding vessels (Cassou sperm straws; Nunc CryoTubes) to generate four different cooling-rate curves during freezing. Sperm motility and viability (47.3% and 76.5% respectively) were highest when frozen in straws suspended in a LN2 bath at an intermediate cooling rate of 73 °C/min between 0 and -50 °C, whereas sperm frozen in straws suspended in a dry shipper at the fastest cooling rate (231 °C/min between 0 and -50 °C) produced the lowest recovery (10.4% and 36.4% motility and viability, respectively). Sperm frozen in cryotubes at the lowest cooling rates in either LN2 bath vapour or dry shipper produced intermediate recovery. The shape of the optimal cooling curve conformed to the two-factor hypothesis of cryoinjury, the first such evidence in reptile sperm. This in turn led to the identification of simple cryopreservation setups (LN2 vapour with straws and cryotubes; dry shipper with cryotubes but not straws) suitable for cryopreserving lizard sperm in the field.

Taxonomy, population status and ecology of Indian desert monitor lizard Varanus griseus koniecznyi Mertens 1954 in the Thar desert of Rajasthan.

Among monitor lizards of the family Varanidae, Indian desert monitor lizard Varanus griseus koniecznyi Mertens 1954 is one of the lesser-known species globally and due to lack of data on this species it is so far not evaluated by IUCN and excluded from the latest assessment of monitor lizards of Southeast Asia and Indo-Australian Archipelago. The present study was undertaken from January 2013 to June 2017 to fill this gap during which taxonomic evaluation along with an assessment of population and ecology of this species was carried out in the Thar desert of Rajasthan (TDR). The study brought into knowledge many morphological variations along with intraspecific variations of scale microstructure of this lizard. The population density was found to be highest in the Jaisalmer (0.102/ha) district of western Rajasthan, followed by Bikaner (0.08/ha) and Sikar (0.077/ha) districts. The overall population was quite low (0.068/ha) in the area. The study further revealed the species is habitat specialist and lives in a narrow range of habitats and microhabitats, and hence, the species may not adapt to the rapidly changing environment in the TDR. Their activity was found to be highest between 9ndash;12 hrs followed by 12–15 hrs and foraging was found to be their predominant activity followed by resting and feeding. In the absence of any detailed study on this species, the study points towards immediate conservation efforts for the species in its current distribution. Baseline data generated through this study will no doubt help to safeguard the species in the TDR and further research on this species in the future.

Online media reveals a global problem of discarded containers as deadly traps for animals

The widespread occurrence of litter is a severe threat to global ecosystems. We have analyzed online media, to assess the diversity of animals that are prone to getting trapped in discarded containers and check which kind of containers is the most common trap for animals. A total of 503 records from around the world (51 countries, 6 continents) have been found. These include invertebrates (17 taxa, ca.1050 dead individuals), and vertebrates (98 taxa, 496 individuals including 44 carcasses). The latter group was most frequently represented by mammals (78.5% of all cases), then reptiles (15.3%), birds (1.2%), fish (1.0%) and amphibians (0.4%). Nearly 12.5% of the determined vertebrates are classified as vulnerable, endangered or critically endangered, according to the IUCN. Although most trapped individuals were smaller animals, bigger ones such as monitor lizards (Varanus spp.) or large carnivores were also recorded. In most cases, animals were trapped in glass or plastic jars (32.4%), drink cans (16.5%), and steel cans (16.3%). Our results demonstrate that discarded containers can be a threat to all major groups of animals. In order to address this phenomenon, it is necessary to decrease a global production of debris, implement container deposit legislation and organize repeatable cleanup actions.

Choose your meals carefully if you need to coexist with a toxic invader

Vulnerable native species may survive the impact of a lethally toxic invader by changes in behaviour, physiology and/or morphology. The roles of such mechanisms can be clarified by standardised testing. We recorded behavioural responses of monitor lizards (Varanus panoptes and V. varius) to legs of poisonous cane toads (Rhinella marina) and non-toxic control meals (chicken necks or chicken eggs and sardines) along 1300 and 2500 km transects, encompassing the toad’s 85-year invasion trajectory across Australia as well as yet-to-be-invaded sites to the west and south of the currently colonised area. Patterns were identical in the two varanid species. Of monitors that consumed at least one prey type, 96% took control baits whereas toad legs were eaten by 60% of lizards in toad-free sites but 0% from toad-invaded sites. Our survey confirms that the ability to recognise and reject toads as prey enables monitor lizards to coexist with cane toads. As toxic invaders continue to impact ecosystems globally, it is vital to understand the mechanisms that allow some taxa to persist over long time-scales.

Parasitic infestation and site preference of the tick Amblyomma gervaisi on the monitor lizard Varanus bengalensis in India

Parasitic infestation and site preference of the tick Amblyomma gervaisi on the monitor lizard Varanus bengalensis in India

Plasticity in nest site choice behavior in response to hydric conditions in a reptile

Natural selection is expected to select for and maintain maternal behaviors associated with choosing a nest site that promotes successful hatching of offspring, especially in animals that do not exhibit parental care such as reptiles. In contrast to temperature effects, we know little about how soil moisture contributes to successful hatching and particularly how it shapes nest site choice behavior in nature. The recent revelation of exceptionally deep nesting in lizards under extreme dry conditions underscored the potential for the hydric environment in shaping the evolution of nest site choice. But if deep nesting is an adaptation to dry conditions, is there a plastic component such that mothers would excavate deeper nests in drier years? We tested this hypothesis by excavating communal warrens of a large, deep-nesting monitor lizard (Varanus panoptes), taking advantage of four wet seasons with contrasting rainfall amounts. We found 75 nests during two excavations, including 45 nests after a 4-year period with larger wet season rainfall and 30 nests after a 4-year period with smaller wet season rainfall. Mothers nested significantly deeper in years associated with drier nesting seasons, a finding best explained as a plastic response to soil moisture, because differences in both the mean and variance in soil temperatures between 1 and 4 m deep are negligible. Our data are novel for reptiles in demonstrating plasticity in maternal behavior in response to hydric conditions during the time of nesting. The absence of evidence for other ground-nesting reptile mothers adjusting nest depth in response to a hydric-depth gradient is likely due to the tradeoff between moisture and temperature with changing depth; most ground-nesting reptile eggs are deposited at depths of ~ 2–25 cm—nesting deeper within or outside of that range of depths to achieve higher soil moisture would also generally create cooler conditions for embryos that need adequate heat for successful development. In contrast, extreme deep nesting in V. panoptes allowed us to disentangle temperature and moisture. Broadly, our data suggest that ground-nesting reptiles can assess soil moisture and respond by adjusting the depth of the nest, but may not, due to the cooling effect of nesting deeper. Our results, within the context of previous work, provide a more complete picture of how mothers can promote hatching success through adjustments in nest site choice behavior.

Locomotor rib kinematics in two species of lizards and a new hypothesis for the evolution of aspiration breathing in amniotes

Most lizards walk and run with a sprawling gait in which the limbs are partly advanced by lateral undulation of the axial skeleton. Ribs and vertebrae are integral to this locomotor mode, but 3D motion of the axial skeleton has not been reported for lizard locomotion. Here, we use XROMM to quantify the relative motions of the vertebrae and ribs during slow treadmill locomotion in three savannah monitor lizards (Varanus exanthematicus) and three Argentine black and white tegus (Salvator merianae). To isolate locomotion, we selected strides with no concurrent lung ventilation. Rib rotations can be decomposed into bucket-handle rotation around a dorsoventral axis, pump-handle rotation around a mediolateral axis, and caliper rotations around a craniocaudal axis. During locomotion, every rib measured in both species rotated substantially around its costovertebral joint (8–17 degrees, summed across bucket, pump and caliper rotations). In all individuals from both species, the middle ribs rotated cranially through bucket and pump-handle motion during the propulsive phase of the ipsilateral forelimb. Axial kinematics during swing phase of the ipsilateral forelimb were mirror images of the propulsive phase. Although further work is needed to establish what causes these rib motions, active contraction of the hypaxial musculature may be at least partly responsible. Unilateral locomotor rib movements are remarkably similar to the bilateral pattern used for lung ventilation, suggesting a new hypothesis that rib motion during locomotion may have been an exaptation for the evolution of costal aspiration breathing in stem amniotes.

Study Anatomy of Vertebrae Caudalis Asiatic Water Monitor (Varanus salvator)

Asiatic water monitor lizard (Varanus salvator) is a type of reptile that can be found in several countries on the Asian continent. In Indonesia this species can be found in the Sunda plain (Java, Bali and Nusa Tenggara) and Maluku (the Sula and Obi islands). Asiatic water monitor lizard is long tailed reptile. The functions of tail as a movement aid, to maintain balance, a place to store energy, sexual appearance, and reproduction. The caudalis vertebrae in asiatic water monitor lizard (Varanus salvator) has a structure consisting of centrum, processus, cotyle, condilus, and constriction area. To observe the caudal vertebrae in monitor lizards the experiment was done by cleaning all the sticky tissue, then observed using a stereo microscope with a magnification of 0.8X. The result showed that blood vessels and nerve tissue were protected by sturdy bones.

Pathological Conditions Associated with Physaloptera Stomach Worm Infestation in Bengal Monitor Lizard Varanus bengalensis

The present study reports pathological conditions associated with Physaloptera sp. stomach worm infestation in Bengal monitor lizard (Varanus bengalensis). Four adult Bengal monitor lizards were rescued from the poachers and kept at Wild Animal Rescue and Rehabilitation Centre, Bannerghatta Biological Park, Bengaluru. Faecal samples from all were collected and examined. Physaloptera sp. ova were found in all faecal samples examined by sedimentation technique. One Bengal monitor lizard died during the period and systematically examined at necropsy for gross pathological lesions. Adult Physaloptera sp. nematodes were found to be firmly attached to the gastric mucosa causing erosive inflammatory foci. Histopathological examination of stomach revealed the presence of many immature and mature worms encapsulated within fibrous connective tissue. The intestinal villi were stunted and many cross sections of the worms could be demonstrated in the lumen. The worms also migrated to liver parenchyma and got encapsulated with fibrous connective tissue with infiltration of eosinophils in the sinusoids and the vascular tissue spaces. This seems to be the first report of Physaloptera sp. nematodiasis in Bengal monitor lizard kept under captivity for a period of 1.5 months.

Active tympanic tuning facilitates sound localization in animals with internally coupled ears

Earlier studies have reported that numerous vertebrate taxa have skeletal muscle(s) attaching directly, or indirectly, onto the tympanic membrane. The present study links these prior studies by quantitatively modeling the influence of skeletal muscle contraction on tympanic tension, tympanic dampening, and, ultimately, the fundamental frequency. In this way, the efficacy of these tympanic muscles to dynamically alter the sensory response of the vertebrate ear is quantified. Changing the tension modifies the eardrum’s fundamental frequency, a key notion in understanding hearing through internally coupled ears (ICE) as used by the majority of terrestrial vertebrates. Tympanic tension can also be modulated by altering the pressure acting on the deep (medial) surface of the tympanum. Herein we use the monitor lizard Varanus as an example to demonstrate how active modulation of the pharyngeal volume permits tuning of an ICE auditory system. The present contribution offers a behaviorally and biologically realistic perspective on the ICE system, by demonstrating how an organism can dynamically alter its morphology to tune the auditory response. Through quantification of the relationships between tympanic surface tension, damping, membrane fundamental frequency, and auditory cavity volume, it can be shown that an ICE system affords a biologically relevant range of tuning.

Identification of Antibacterial Molecule(s) from Animals Living in Polluted Environments.

Snakes feed on germ-infested rodents, while water monitor lizards thrive on rotten matter in unhygienic conditions. We hypothesize that such creatures survive the assault of superbugs and are able to fend off disease by producing antimicrobial substances. In this study, we investigated the potential antibacterial activity of sera/lysates of animals living in polluted environments. Snake (Reticulatus malayanus), rats (Rattus rattus), water monitor lizard (Varanus salvator), frog (Lithobates catesbeianus), fish (Oreochromis mossambicus), chicken (Gallus gallus domesticus), and pigeon (Columba livia) were dissected and their organ lysates/sera were collected. Crude extracts were tested for bactericidal effects against neuropathogenic E. coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Bacillus cereus and Klebsiella pneumoniae. To determine whether lysates/sera protect human cells against bacterialmediated damage, cytotoxicity assays were performed by measuring lactate dehydrogenase release as an indicator of cell death. Lysates/sera were partially characterized using heat-treatment and pronasetreatment and peptide sequences were determined using the Liquid Chromatography Mass Spectrometry (LC-MS). Snake and water monitor lizard sera exhibited potent broad-spectrum bactericidal effects against all bacteria tested. Heat inactivation and pronase-treatment inhibited bactericidal effects indicating that activity is heat-labile and pronase-sensitive suggesting that active molecules are proteinaceous in nature. LCMS analyses revealed the molecular identities of peptides. The results revealed that python that feeds on germ-infested rodents and water monitor lizards that feed on rotten organic waste possess antibacterial activity in a heat-sensitive manner and several peptides were identified. We hope that the discovery of antibacterial activity in the sera of animals living in polluted environments will stimulate research in finding antibacterial agents from unusual sources as this has the potential for the development of novel strategies in the control of infectious diseases.